Special measures are being taken at the Miami Zoo to protect two highly endangered clouded leopard cubs that are vulnerable to catching coronavirus.
The cubs - one male and one female - were born on 11 February but have since been secluded in their den to allow time to bond with their mother.
Last month, a tiger at another US zoo tested positive for coronavirus.
The Miami zoo says staff are wearing gloves and masks and disinfecting their shoes when they handle the leopards.
During their examination and vaccinations on Tuesday, the newborns were confirmed by zookeepers to be "developing well".
"Both offspring appear to be thriving and the mother continues to be attentive and nursing them on a regular basis," Zoo Miami said in a statement.
"With the challenges of the Covid-19 pandemic and the recent revelation that a tiger had contracted the disease at another zoological facility, extra care is being taken by all staff working around these kittens.
"New procedures include stepping into disinfecting footbaths prior to entering any feline area as well as using masks and gloves while working in those areas. "
Last month, a 4-year-old Malayan tiger at the Bronx Zoo was confirmed by testing to have Covid-19. Researchers say it's likely that the tiger, named Nadia, was infected by one of her zookeepers.
Six other lions and tigers at the zoo also displayed symptoms, such as dry coughing and loss of appetite, that led biologists to believe that they too were sick.
"This is the first time that any of us know of anywhere in the world that a person infected the animal and the animal got sick," Paul Calle, the chief veterinarian at the zoo, told Reuters news agency.
There have been isolated instances of pets testing positive for the coronavirus elsewhere in the world, but experts have stressed there is no evidence they can become sick or spread the disease.
Clouded leopards are a secretive cat native to forests in southern China, Taiwan, and Malaysia.
Adults usually weigh between 30 to 50lbs (14-23kg).
They are highly-endangered throughout their natural habitat due to over-hunting.
Zoo Miami is currently closed due to shelter-at-home orders, but said in their statement that when the pandemic is finally over, they hope that guests will come visit the clouded leopards in person.